KB ID 0001476
When attempting to connect to a Cisco ASA firewall via SSH you see the following error;
The first key-exchange algorithm supported by the server is diffie-hellman-group1-sha1, which is below the configured warning threshold.
Do you want to continue with this connection?
Clicking ‘Yes’ will let you connect.
When connected, execute the following commands;
ssh key-exchange group dh-group14-sha1